scholarly journals A Coherent Performance for Noncoherent Wireless Systems Using AdaBoost Technique

2019 ◽  
Vol 9 (2) ◽  
pp. 256 ◽  
Author(s):  
Heba Gamal ◽  
Nour Eldin Ismail ◽  
M. R. M. Rizk ◽  
Mohamed E. Khedr ◽  
Moustafa H. Aly

Boosting is a machine learning approach built upon the idea of producing a highly precise prediction rule by combining many relatively weak and imprecise rules. The Adaptive Boosting (AdaBoost) algorithm was the first practical boosting algorithm. It remains one of the most broadly used and studied, with applications in many fields. In this paper, the AdaBoost algorithm is utilized to improve the bit error rate (BER) of different modulation techniques. By feeding the noisy received signal into the AdaBoost algorithm, it is able to recover the transmitted data from the noisy signal. Consequently, it reconstructs the constellation diagram of the modulation technique. This is done by removing the noise that affects and changes the signal space of the data. As a result, AdaBoost shows an improvement in the BER of coherently detected binary phase shift keying (BPSK) and quadrature phase shift keying (QPSK). The AdaBoost is next used to improve the BER of the noncoherent detection of the used modulation techniques. The improvement appears in the form of better results of the noncoherent simulated BER in comparison to that of the theoretical noncoherent BER. Therefore, the AdaBoost algorithm is able to achieve a coherent performance for the noncoherent system. The AdaBoost is simulated for several techniques in additive white Gaussian noise (AWGN) and Rayleigh fading channels so, as to verify the improving effect of the AdaBoost algorithm.

2019 ◽  
Vol 7 (1) ◽  
pp. 30-39
Author(s):  
Fatima faydhe Al- Azzawi ◽  
Faeza Abas Abid ◽  
Zainab faydhe Al-Azzawi

Phase shift keying modulation approaches are widely used in the communication industry. Differential phase shift keying (DPSK) and Offset Quadrature phase shift keying (OQPSK) schemes are chosen to be investigated is multi environment channels, where both systems are designed using MATLAB Simulink and tested. Cross talk and unity of signals generated from DPSK and OQPSK are examined using Cross-correlation and auto-correlation, respectively. In this research a proposed system included improvement in bit error rate (BER) of both systems in  the additive white Gaussian Noise (AWGN) channel, by using the convolutional and block codes, by increasing the ratio of energy in the specular component to the energy in the diffuse component (k) and  the diversity order BER in the fading channels will be improved in both systems.    


The digital modulation methods are being chosen in high data rate systems as Long Term Evolution (LTE) and LTE-A. Quadrature Phase Shift Keying (QPSK) and Binary Phase Shift Keying (BPSK) is the simplest form of the PSK with double carrying capacity when compare to the other traditional techniques in modulation. In conventional method the performance was analyzed in MIMO .In this paper proposed the performance analysis of BPSK and QPSK modulator and demodulator in LTE 4G system models under the Additive white Gaussian Noise (AWGN) and Rayleigh fading by comparing the Bit Error Rate (BER). From the analysis, compare to BPSK QPSK has good BER. Using the MATLAB Simulink tool Implementation is performed.


2017 ◽  
Vol 7 (1.1) ◽  
pp. 418
Author(s):  
M Kanthimathi ◽  
R Amutha ◽  
S Anusha

Modulation diversity can reduce the bit error rate in fading channels. We make use of the advantage of modulation diversity in non-coherent differential modulation technique. Increase in modulation diversity is obtained by rotating signal constellation. Coordinate interleaved Differential amplitude and phase-shift keying modulation (DAPSK) is particularly advantageous compared to the Differential phase-shift keying (DPSK) technique. Energy optimization is done to minimize the energy consumption. Simulation results shows that the proposed differential detection for different rotation angle achieves better BER performance than constant phase differential detection with modulation diversity.The energy required to successfully transmit a bit is also reduced for proposed system compared to Differential phase shift keying based system.


Author(s):  
Md. Firoz Ahmed ◽  
Md. Faysal Ahmed ◽  
Abu Zafor Md. Touhidul Islam

Digital modulation increases information capacity, data security, and system availability while maintaining high communication quality. As a result, digital modulation techniques are in higher demand than analog modulation techniques due to their ability to transmit larger amounts of data. Amplitude Shift Keying (ASK), Frequency Shift Keying (FSK), Phase Shift Keying (PSK), Differential Phase Shift Keying (DPSK), and Quadrature Amplitude Modulation (QAM) are critical components of current communications systems development, particularly for broadband wireless communications. In this paper, the comparison of bit error rate performance of different modulation schemes (BPSK, QPSK, and16-QAM) and various equalization techniques such as constant modulus algorithm (CMA) and maximum likelihood sequence estimate (MLSE) for the AWGN and Rayleigh fading channels is analyzed using Simulink. BPSK outperforms QPSK and 16-QAM when compared to the other two digital modulation schemes. Among the three digital modulation schemes, BPSK is showing better performance as compared to QPSK and 16-QAM.


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